It seems like the connection to the network drive was lost then. I am not sure how much we can do about preventing those crashes when the connection is lost while reading a file, so please keep in mind: Loading files from the network is generally okay as long as the network connection is stable.

It is generally a bad idea to run OpenMPT itself from a network drive for the same reason. Windows might page out parts of the executable and then crash when trying to load them from the drive while it is unavailable.

We will stop using memory-mapped files in OpenMPT 1.29 but due to the complexity of these changes, it is unlikely they will be backported to OpenMPT 1.28. If you experience these crashes frequently and loading files from network is very important to you, consider using test builds for OpenMPT 1.29: https://builds.openmpt.org/builds/